原文鏈接
第5章 流暢的API(fluent API)
5.1. 易用的API
從版本4.2開始趋距，HttpClient提供了一個易于使用的API粒氧，它基于流暢的接口概念。該API僅公開HttpClient的最基本功能节腐，適用于不需要HttpClient完全靈活性的簡單用例外盯。例如，該API使用戶不必處理連接管理和資源釋放翼雀。
以下是通過HC fluent API執(zhí)行的HTTP請求的幾個示例
// Execute a GET with timeout settings and return response content as String.
Request.Get("http://somehost/")
.connectTimeout(1000)
.socketTimeout(1000)
.execute().returnContent().asString();
// Execute a POST with the 'expect-continue' handshake, using HTTP/1.1,
// containing a request body as String and return response content as byte array.
Request.Post("http://somehost/do-stuff")
.useExpectContinue()
.version(HttpVersion.HTTP_1_1)
.bodyString("Important stuff", ContentType.DEFAULT_TEXT)
.execute().returnContent().asBytes();
// Execute a POST with a custom header through the proxy containing a request body
// as an HTML form and save the result to the file
Request.Post("http://somehost/some-form")
.addHeader("X-Custom-header", "stuff")
.viaProxy(new HttpHost("myproxy", 8080))
.bodyForm(Form.form().add("username", "vip").add("password", "secret").build())
.execute().saveContent(new File("result.dump"));
也可以直接使用Executor饱苟，以便在特定的安全上下文中執(zhí)行請求，從而對身份驗證詳細信息進行緩存并重新用于后續(xù)請求狼渊。
Executor executor = Executor.newInstance()
.auth(new HttpHost("somehost"), "username", "password")
.auth(new HttpHost("myproxy", 8080), "username", "password")
.authPreemptive(new HttpHost("myproxy", 8080));
executor.execute(Request.Get("http://somehost/"))
.returnContent().asString();
executor.execute(Request.Post("http://somehost/do-stuff")
.useExpectContinue()
.bodyString("Important stuff", ContentType.DEFAULT_TEXT))
.returnContent().asString();
5.1.1. 響應(yīng)處理
流暢的外觀API通常使用戶不必處理連接管理和資源釋放箱熬。但是，在大多數(shù)情況下狈邑，這需要在內(nèi)存中緩沖響應(yīng)消息的內(nèi)容坦弟。強烈建議使用ResponseHandler進行HTTP響應(yīng)處理，以避免在內(nèi)存中緩沖內(nèi)容官地。
Document result = Request.Get("http://somehost/content")
.execute().handleResponse(new ResponseHandler<Document>() {
public Document handleResponse(final HttpResponse response) throws IOException {
StatusLine statusLine = response.getStatusLine();
HttpEntity entity = response.getEntity();
if (statusLine.getStatusCode() >= 300) {
throw new HttpResponseException(
statusLine.getStatusCode(),
statusLine.getReasonPhrase());
}
if (entity == null) {
throw new ClientProtocolException("Response contains no content");
}
DocumentBuilderFactory dbfac = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder docBuilder = dbfac.newDocumentBuilder();
ContentType contentType = ContentType.getOrDefault(entity);
if (!contentType.equals(ContentType.APPLICATION_XML)) {
throw new ClientProtocolException("Unexpected content type:" +
contentType);
}
String charset = contentType.getCharset();
if (charset == null) {
charset = HTTP.DEFAULT_CONTENT_CHARSET;
}
return docBuilder.parse(entity.getContent(), charset);
} catch (ParserConfigurationException ex) {
throw new IllegalStateException(ex);
} catch (SAXException ex) {
throw new ClientProtocolException("Malformed XML document", ex);
}
}
});
